Michael Mikowski has a post to his site that suggests that a RESTful API is a big lie and that the concept should "rest in piece" and be replaced with something he calls a "JSON-pure API".

If you have read an internet developer resume or job posting in the past 10 years, then you might be forgiven if you think that RESTful APIs are gifts bestowed from the heavens by The One True Web Developer Deity. RESTful APIs are everywhere. Even the marketing folks are pushing them in sales material intended for CEOs and Human Resources-type folks. So how good of an idea are RESTful APIs really?

He starts with a look at where the concepts for a RESTful API originally came from and defines some of the most common concepts around them (verbs, request/response, etc). He then suggests that they're "pretty awful" and lists some of the larger problems he sees with them:

Problem #1: There is little agreement on what a RESTful API is

Problem #2: The REST vocabulary is not fully supported

Problem #3: The REST vocabulary is not rich enough for APIs

Problem #4: RESTful APIs are very hard to debug

Problem #5: RESTful APIs are usually tied to HTTP

He suggests that the way to move forward is to migrate to the "JSON-pure API" methodology, fixing most of the problems he listed. He describes this kind of API and how it simplifies the entire process and makes it "more reliable, easier to use, easier to port, and easier to debug."